Three-way flap valves are also referred to as three-way butterfly valves. Three-way flap valves are characterized by the number of inlets and outlets being precisely three.
The heat energy recovery mechanism may, for instance, be a latent heat accumulator, an energy generator operating in accordance with the Rankine cycle, a Schukey engine operating in an Organic Rankine Cycle (OCR process), or just a heat exchanger for heating a coolant.
The exhaust gas treatment for internal combustion engines is usually configured from passive systems that are all in all passed through by the exhaust gas during all operational conditions. When passing through the system, the exhaust gas flow suffers a certain resistance that reduces the overall efficiency of the system. To reduce emissions and exhaust noise under operating conditions with lower partial load such as in normal traffic situations, switchable systems with position members are used allowing to seal or disconnect parts of the exhaust system and to use only portions of it.
From DE 10 2012 107 839 A1 a four-way exhaust flap is known that serves that purpose. A drawback of this known exhaust flap is its high flow resistance.
Further, it is known to charge a latent heat accumulator using the engine heat of a motor vehicle and to release the energy stored in the latent heat accumulator on cold starts.